In a small bowl mix the brown sugar, paprika, garlic powder, chili powder, onion powder, cumin, thyme, salt, and pepper. Spread it evenly over the entire rack of ribs, careful to press it on.
Add the water, vinegar, liquid smoke and ½ cup of BBQ sauce to the instant pot and mix.
Place the ribs in the instant pot in a standing position.
Close the vent and set the meat setting to 23 minutes.
Line a baking sheet with tinfoil and place the ribs on the sheet.
When the timer is finished, let the meat slow release for 5 minutes, then do a quick release and remove from the instant pot and place on prepared baking sheet.
Turn the oven to high broil. Spread the remaining BBQ sauce over the ribs. Place under the broiler and watch carefully.
When the BBQ sauce is bubbly and slightly browned, it is finished. This may take 2 to 5 minutes and can burn quickly.
Remove and enjoy with your favorite side dishes.